Mango leaf extract incorporated chitosan antioxidant film for active food packaging

Abstract

Health hazards associated with usage of plastic films for food preservation demands for development of active films from non-toxic and antioxidant rich bio-sources. The reported work highlights the development, characterization and application studies of chitosan films enhanced for their antioxidant activity by mango leaf extract (MLE) incorporation. Effect of MLE variation (1-5%) on the morphology, optical nature, water exposure and mechanical characteristics of the chitosan-MLE composite films was studied. Increase in the MLE concentration resulted in films with increased thickness and decreased moisture content. Contact angle, water solubility and vapor permeability analysis demonstrated the reduced hydrophilicity and water vapor penetrability of the films due to MLE inclusion. MLE films possessed better tensile strength (maximum of 23.06 ± 0.19 MPa) with reduced elongation ratio than the pure chitosan film (18.14 ± 0.72 MPa). Antioxidants assessment in terms of total phenolic content, DPPH radical scavenging, ferric reducing power and ABTS radical scavenging showed improved antioxidant activity with the incremental amounts of MLE in the chitosan films. Microscopic studies revealed the smooth, compact and dense nature of the MLE-chitosan films favouring low oxygen transport rates. Application studies to cashew nuts preservation for 28 days storage indicated 56% higher oxidation resistance for the 5% MLE film than a commercial polyamide/polyethylene film. Results highlight the potential and promising nature of MLE impregnated chitosan films as suitable alternative for active packaging films for food preservation.

Keywords: Active packaging; Antioxidant film; Cashew nuts preservation; Chitosan; Mango leaves.